Cylinder bed sewing machine



July 21 1970 v J. ROUHA 3,521,535

CYLINDER BED SEWING MACHINE Filed March 4; 1969 INVENTOR av: 8! ma ATTORNEY United States Patent 3,521,585 CYLINDER BED SEWING MACHINE Josef Rouha, Boskovice, Czechoslovakia, assignor to Elitex Zavody Tertilniho Strojirenstvi Generalni Reditelstvi, Liberec, Czechoslovakia Filed Mar. 4, 1969, Ser. No. 804,155 Claims priority, application Czechoslovakia,

Mar. 5, 1968, 1,716/68 Int. Cl. D05b 27/00 US. Cl. 112-406 Claims ABSTRACT OF THE DISCLOSURE A cylinder bed sewing machine with bottom and needle advancement of the workpiece, wherein the needle and the feeder are moved up and down by two rotary shafts and are oscillated by two additional shafts. The additional shafts derive oscillatory motion from one of the rotary shafts by way of an eccentric.

BACKGROUND OF THE INVENTION The present invention relates to a cylinder bed sewing machine with bottom and needle advancement of tthe workpiece.

Sewing machines with needle feed of the workpiece are used in those instances where the application of bottom feeding would be insufiicient for attaining simultaneous advancement of two or more layers of material. The feeding element acts only upon the lowermost layer while its motion is transmitted to the upper layer by friction between the lower and upper layers. Moreover, the layers to be sewn are pressed together from above by means of a presser foot, the friction of which against the upper layer tends to prevent or delay motion of the upper layer with the lower layer or layers. Under certain circumstances, namely when the surfaces of the layers to be sewn are too smooth, the bottom feeding does not reliably ensure the feeding of each layer and allows the risk of their mutual displacement especially during an extended sewing operation.

In order to overcome this drawback, it is presently known to use the technique of needle advancement wherein the needle has two simultaneous motions, the first being vertically reversible to penetrate the workpiece, and a second which in conjunction with the motion of the feeder advances the workpiece. Such simultaneous motions are accomplished by deriving the respective feeding motions of the feeder and the needle from a common element such as an eccentric. The term feeding motion, as it is used herein, is defined as a motion in the direction of advancement of the workpiece during the sewing process; or a corresponding component of the composite motion of the needle or the feeder.

The driving devices for the feeding mechanisms of conventional sewing machines having bottom and needle advancement are made such that the driving device is mounted in the upper part of the sewing machine bed and the transmission to the upper and lower feeding shafts is performed by means of a system of motion transmitting rods and tie rods.

By mounting the driving mechanism for the feeder in the upper cylinder bed so that it is considerably above the center of gravity of the sewing machine, which is usually in the plane of sewing, considerable vibration of the machine occurs, thereby causing noise and reducing the operative life of the machine.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel driving device for a feeding mechanism of a cylinder bed sewing machine.

Another object of the invention is to provide a cylinder bed sewing machine in which the vibration and noise is less than that in a conventional sewing machine.

Another object of the invention is to provide a driving device for a feeding mechanism of a cylinder bed sewing machine which is simpler in design and more economical to use than present configurations.

The improved sewing machine comprises two work advancing members arranged on opposite sides of the path of a workpiece, rotary input means, two rotary first output members driven by the input means and each connected with one of the advancing members to effect reciprocating the movements of the respective advancing member, two oscillatory second output members, each connected with one of the advancing members to effect oscillatory movements of the respective advancing member, and motion transmitting means deriving motion from one of the first output members and operative to effect oscillatory movements of the second output members. The one first output member is located at a level below the other first output member.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved sewing machine itself, however, both as to its construction and its method of operation, together with additional features and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view of one embodiment of the invention using one form of motion transmitting means; and

FIG. 2 is a schematic illustration of an alternative motion transmitting means which can be used in the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, FIG. 1 shows a sewing machine with bottom and needle feed, comprising a frame 1, rotary input means 2, rotary output members 5 and 11, oscillatory output members 17 and 20, and work advancing members 8 and 13. The work advancing member 8 is a needle and the other work advancing member 13 is a serrated feeder. Each of the output members is a horizontal shaft and all four shafts are. parallel to each other.

Frame 1 comprises a column 1a, and a lower arm 3 for shafts 11 and 20, and an upper arm 4 for shafts 5 and 17. 'The arms 3 and 4 are substantially horizontal and project from the column and are constructed such that there is a gap between their ends, as shown in FIG. 1. Rotary input means 2 is positioned at one end of the frame as shown and drives the rotary output members by means of a drive train 21. The oscillatory output members 17 and 20 derive their respective motions from the rotary output member 11 through a motion transmitting unit which comprises an eccentric 14, a strap 15a cooperating with the eccentric and two link trains which are moved by the strap.

The shaft 5 imparts reciprocatory up and down motion to needle rod 7 by means of a crank mechanism 6. Needle rod 7 with needle 8 is guided through holder 9 and is swingably mounted about pivot 10. In the lower arm 3, the other rotary shaft 11 is conventionally mounted and has an eccentric 12. firmly secured thereto, the purpose of the eccentric being to impart a vertical component of the combined motion of the shaft and the eccentric to feeder 13.

The feeding motions of the needle 8 and feeder 13 are derived from the motion of eccentric 14 which rotates with shaft 11. Eccentric 14 is mounted normal to the longitudinal axis of shaft 11. The devices which are used to hold eccentric 14 and fix its position transversely to the longitudinal axis of shaft 11 do not form part of this invention and are therefore not shown.

Eccentric 14 is enclosed by strap 15a at one end of eccentric rod 15, the other end 15b of which is connected by means of a pivot (not shown) to one end of link 16, these elements considered together constituting a first link train. The longitudinal axis of link 16 is perpendicular to the longitudinal axis of the oscillatory output shaft 17. The other end of link 16 is connected to shaft 17 by means of a strap and set screw (not shown) in such a manner that the swinging motion of lever 16, which is derived from the motion of eccentric rod '15, causes an oscillatory motion of shaft 17. As it is used herein, as Well as in the appended claims, the term oscillatory motion, particularly in relation to the motion of a shaft, means the rotary motion of a shaft about its longitudinal axis with a corresponding periodical change in the direction of the rotary motion.

Referring again to FIG. 1, a projection 19 is mounted on eccentric rod 15 and is slidable in guideway or follower 22a at one end of tie rod 22. The other end 22b of the tie rod 22 is connected to oscillatory output shaft 20 by a fastener means, these elements considered together constituting a second link train.

The operation is as follows:

Shaft 5, by means of drive train 21 transmits rotary unidirectional motion to rotary output shaft 11, the rotary motion of which is shared by eccentric 14. The motion of eccentric 14 is transmitted through eccentric rod 15 and link 16 to cause an oscillatory motion of shaft 17, which motion is transmitted by means of crank 18 to holder 9 of needle rod 7 in the form of a swinging motion of holder 9 about pivot The motion of eccentric rod is transmitted by means of tie rod 22 to shaft in a manner analogous to that of shaft 17 which also imparts an oscillatory motion to feeder 13 by means of joint link 23. v

In the embodiment shown in FIG. 1, the length of the stroke of the feeding motion of feeder 13 can be shortened if the projection 19 is placed nearer to the strap 15a, assuming that all other conditions remain the same. The reverse is also true, i.e., that the stroke of feeder 13 will lengthen as the projection 19 is located farther away from strap 15a. The length of the stroke of needle 8 is not affected in any way by the position of projection 19 on eccentric rod 15.

By mounting the motion transmitting unit in the lower portion of the sewing machine the center of gravity of the machine is lowered, and oscillation and noise are thereby reduced.

When choosing additional elements which would also determine the length of the feeding motion of needle 8 and feeder 13, for example the length of links 16 and 23 or the distance of pivot 10 from the cloth plate, a position of the projection '19 can be found at which the length of the effective motion of needle 8 equals the length of the effective feeding motion of feeder 13. It is possible to synchronize these two motions by deriving their individual motion from the motion of eccentric rod 15.

Because of the fact that eccentric 14 is mounted normal to the direction of the longitudinal axis of shaft 11, it is possible to change the length of the stroke of the feeding motion of feeder 13 and needle 8, without changing the mutual ratio of these lengths.

FIG. 2 shows an alternative embodiment of a part of the driving device. Eccentric rod 15 is movably connected wit-h tie rod 22 by means of an articulated link 31. One end of link 31 is rotatably fastened to a pivot 32 mounted 4 on eccentric rod 15 and the other end is rotatably connected to tie rod 22.

In this embodiment it is also possible to achieve a congruence between the length of the strokes of the respective feeding motions of needle 8 and feeder 13 by selecting a link 31 which has a suitable length for this purpose.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of the above-mentioned contribution to the art.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In a sewing machine, two work advancing members arranged on opposite sides of the path of a workpiece; rotary input means; two rotary first output members driven by said rotary input means and each connected with one of the advancing members to effect reciprocatory movements of the respective advancing member; two oscillatory second output members, each connected with one of the advancing members to effect oscillatory movements of the respective advancing member; and motion transmitting means deriving motion from one of said first output members and operative to effect oscillatory movements of said second output members, said one first output member being located at a level below the other first output member.

2. A combination as defined in claim 1, wherein the work advancing member which receives reciprocatory motion from said one first output member is a feeder and wherein the other work advancing member is a needle.

3. A combination as defined in claim 2, wherein each of said output members is a substantially horizontal shaft, and wherein said shafts are parallel to each other.

4. A combination as defined in claim 1, further comprising a frame having an upper portion and a lower portion, said one first output member and its corresponding second output member being mounted in said lower portion, and the remaining output members being mounted in said upper portion.

5. A combination as defined in claim 1, wherein said motion transmitting means comprises a rotary eccentric driven by said one first output member, a strap cooperating with said eccentric, a first link train connecting said strap with one of said second output members and a second link train connecting said strap with the other second output member.

6. A combination as defined in claim 5, wherein one of said link trains is connected with the strap by way of the other link train.

7. A combination as defined in claim 1, wherein said rotary input means comprises a drive train.

8. A combination as defined in claim 1, wherein the work advancing members oscillate in a plane normal to the axes of the second output members.

9. A combination as defined in claim 1, wherein the connection between one of said advancing members and the respective first output member comprises an eccentric which is rotated by said last mentioned output member.

10. A combination as defined in claim 1, wherein the connection between one of said advancing members and the corresponding first output member comprises a crank mechanism.

11. A combination as defined in claim 1, wherein the connection between one of said advancing members and the respective second output member comprises a link which is articulated to each of the said last-mentioned members.

12. A combination as defined in claim 1, wherein the connection between one of said advancing members and 5 the respective second output member comprises a crank mechanism.

13. A combination as defined in claim 6, wherein Said other link train comprises an eccentric rod connected with said strap and arranged to oscillate in response to rotation of said eccentric; and wherein said one link train comprises an arm rigid with the corresponding second output member and means for oscillating said arm in response to the oscillation of said eccentric rod.

14. A combination as defined in claim 13, wherein the means for oscillating said arm comprises a follower provided on said arm and a projection provided on said eccentric rod, said projection slidably engaging said follower.

6 15 A combination as defined in claim 13, wherein the means for oscillating said arm comprises a link articulately connected to said eccentric rod and to said arm.

References Cited UNITED STATES PATENTS 1,685,436 9/1928 Ringe 112206 3,198,154 8/1965 Reeber 112-206 X 3,285,210 11/1966 Tretow et a1 112206 PATRICK D. LAWSON, Primary Examiner 

